快来看JS的的几个常用算法（持续更新中）

// 第一种方法
  let arr = [1,1,2,3,4];
  function fun(v) {
    return Array.from(new Set(v))
  }
  console.log(fun(arr)) //[1,2,3,4]
  // 第二种方法
  let qc= [...new Set(arr)]
  console.log(qc) //[1,2,3,4]

let arr0 = ['a','b','c'];
  let arr2 = ['c','d'];
  let a=new Set(arr0);
  let b=new Set(arr2);
  let bj = new Set([...a,...b]);
  console.log(bj);//{"a", "b", "c", "d"}

let jj = new Set([...a].filter(x=>b.includes(x)));
  console.log(jj);//{"c"}

let cj = new Set([...a].filter(x=>!b.includes(x)));
  console.log(cj);//{"a", "b"}

let arr6=['a','a','a','b','c','c'];
  let arr6obj=arr6.reduce(function(obj,name){
    obj[name]=obj[name]?++obj[name]:1;
    return obj;
  },{})
  console.log(arr6obj)// {a: 3, b: 1, c: 2}

let arr7=[2,3,10];
  const arro=arr7.reduce(function(list,num){
    num=num*2;
    if(num>=20){
      list.push(num)
    }
    return list;
  },[])
  console.log(arro);//[20]

let num1='1' * 1;
  console.log(typeof num1) //number

let jz=[0,null,false,NaN,1,2];
  const filter1=arr1=>arr1.filter(Boolean);
  console.log(filter1(jz)) //[1,2]

let num2=1.223;
  console.log(num2|0);//1

let num3=3;
  console.log(!!(num3 & 1));//true

let num4=6.222;
  console.log(num4.toFixed(1));//6.2

let [rr,aa]=[1,2];
  console.log(rr);//1

[rr,aa]=[aa,rr];
  console.log(rr);//2

let ee=[1,12];
  let ongjj={
    name:'maomin'
  }
  function isType(arr) {
      return Object.prototype.toString.call(arr) 
  } 
  console.log(isType(ee));//[object Array]
  console.log(isType(ongjj));//[object Object]

let stringobj='{"id":0,"name":"张三","age":12}';
  let d3=JSON.parse(stringobj);
  console.log(d3)//{id: 0, name: "张三", age: 12}

let objj={
    id:0,
    name:'maomin'
  }
  let d4=JSON.stringify(objj)
  console.log(d4);//{"id":0,"name":"maomin"}

let stringww="a,b,c,d,e,f";
  console.log(stringww.split(","))//["a", "b", "c", "d", "e", "f"]

let arr9=['l','o','v','e'];
  console.log(arr9.join('-'))

var stre="a,b,c,d";
  function clear(str) { 
    str = str.replace(/,/g, "");//取消字符串中出现的所有逗号 
    return str; 
  }
  console.log(clear(stre))//abcd